Sql ROWID用于筛选列的伪列： CREATE OR REPLACE PROCEDURE DEL_OBS( cuantos number ) IS BEGIN DELETE FROM OBSERVATIONS WHERE ROWID IN ( SELECT rid FROM ( SELECT ROWID AS rid FROM observations ORDER BY DBMS_RANDOM.VALUE ) WHERE ROWNUM < cuantos ); END del_obs;

使用索引查询3：

DELETE FROM table_name
WHERE ROWID IN (
  SELECT rid
  FROM   (
    SELECT ROWID AS rid
    FROM   table_name
    ORDER BY DBMS_RANDOM.VALUE
  )
  WHERE ROWNUM <= 10000
)

---

问题是，你想做什么？为什么要删除记录的随机子集？@APC这不是我的代码，我只是想改进它的执行优化意味着更高效地产生相同的结果。当我们不理解原始代码应该做什么时，IP很难做到这一点。代码本身就很慢。如果您无法重写它，则无法使其更快（因为访问路径是主键）。因此，您需要回到为您设置此任务的人那里，并解释不重写代码就不可能提高代码的性能。数据库是引擎，更像是机械设备，而不是一袋魔豆。唯一的其他选择是：（1）先删除大部分数据，这样剩余的数据集会更小，随机排序会更快，（2）向服务器添加更多的RAM，并增加缓冲池以容纳整个表，无论它有多大，（3）升级到更强大的服务器，具有更高的CPU和I/O性能。问题是，你想做什么？为什么要删除记录的随机子集？@APC这不是我的代码，我只是想改进它的执行优化意味着更高效地产生相同的结果。当我们不理解原始代码应该做什么时，IP很难做到这一点。代码本身就很慢。如果您无法重写它，则无法使其更快（因为访问路径是主键）。因此，您需要回到为您设置此任务的人那里，并解释不重写代码就不可能提高代码的性能。数据库是引擎，更像是机械设备，而不是一袋魔豆。唯一的其他选择是：（1）先删除大部分数据，这样剩余的数据集会更小，随机排序会更快，（2）向服务器添加更多的RAM，并增加缓冲池以容纳整个表，无论它有多大，（3）升级到更强大的服务器，具有更高的CPU和I/O性能。感谢您的提示，但我无法更改查询，这是一个给定的代码，我们不允许接触。我们只能添加外部改进，使用索引或更改PCTFREE和PCTUSED…感谢您的提示，但我无法更改查询，这是我们不允许接触的给定代码。我们只能添加外部改进，使用索引或更改PCTFREE和PCTUSED…感谢您的帮助，但我无法更改代码，只能在事后进行改进：感谢您的帮助，但我无法更改代码，只能在事后进行改进：我会尝试，但到目前为止，我不明白该索引有何帮助，如果该索引是由DBMS创建的（nplate和odatetime是观察的PK，很抱歉我没有这么说），那么该索引已经存在了。您可以通过显示表的DDL脚本轻松地验证这一点。我会尝试一下，但现在我不明白该索引有什么帮助，如果该索引是由DBMS创建的（nplate和odatetime是观察结果的PK，很抱歉我没有这么说），那么该索引已经存在。您可以通过显示表的DDL脚本轻松验证这一点。

 CREATE INDEX cuantos ON OBSERVATIONS(nplate, odatetime);

CREATE OR REPLACE PROCEDURE DEL_OBS(cuantos number) IS
begin

   DELETE OBSERVATIONS  FROM OBSERVATIONS 
   join (select * from  OBSERVATIONS ORDER BY VALUE ) as i on
            nplate=i.nplate AND 
            odatetime=i.odatetime  AND 
            i.ROWNUM<=cuantos;
End DEL_OBS;

SELECT * FROM (
  SELECT * 
  FROM observations 
  ORDER BY DBMS_RANDOM.VALUE)
  WHERE ROWNUM<=cuantos;

AND rowid IN 
   ( SELECT obs_sample.rowid 
     FROM observations sample (0.05) obs_sample)

FROM observations

FROM observations SAMPLE (0.05)

CREATE OR REPLACE PROCEDURE DEL_OBS(
  cuantos number
)
IS
BEGIN
  DELETE FROM OBSERVATIONS
  WHERE ROWID IN (
    SELECT rid
    FROM   (
      SELECT ROWID AS rid
      FROM   observations
      ORDER BY DBMS_RANDOM.VALUE
    )
    WHERE ROWNUM < cuantos
  );
END del_obs;

CREATE TABLE table_name ( id ) AS
SELECT LEVEL FROM DUAL CONNECT BY LEVEL <= 50000;

DELETE FROM table_name
WHERE ROWID IN (
  SELECT rid
  FROM   (
    SELECT ROWID AS rid
    FROM   table_name
    ORDER BY DBMS_RANDOM.VALUE
  )
  WHERE ROWNUM <= 10000
)

----------------------------------------------------------------------------------------
| Id  | Operation                      | Name       | Rows  | Bytes  | Cost | Time     |
----------------------------------------------------------------------------------------
|   0 | DELETE STATEMENT               |            |     1 |     24 |  123 | 00:00:02 |
|   1 |   DELETE                       | TABLE_NAME |       |        |      |          |
|   2 |    NESTED LOOPS                |            |     1 |     24 |  123 | 00:00:02 |
|   3 |     VIEW                       | VW_NSO_1   | 10000 | 120000 |  121 | 00:00:02 |
|   4 |      SORT UNIQUE               |            |     1 | 120000 |      |          |
| * 5 |       COUNT STOPKEY            |            |       |        |      |          |
|   6 |        VIEW                    |            | 19974 | 239688 |  121 | 00:00:02 |
| * 7 |         SORT ORDER BY STOPKEY  |            | 19974 | 239688 |  121 | 00:00:02 |
|   8 |          TABLE ACCESS FULL     | TABLE_NAME | 19974 | 239688 |   25 | 00:00:01 |
|   9 |     TABLE ACCESS BY USER ROWID | TABLE_NAME |     1 |     12 |    1 | 00:00:01 |
----------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
------------------------------------------
* 5 - filter(ROWNUM<=10000)
* 7 - filter(ROWNUM<=10000)

ALTER TABLE table_name ADD CONSTRAINT tn__id__pk PRIMARY KEY ( id )

DELETE FROM table_name
WHERE ROWID IN (
  SELECT rid
  FROM   (
    SELECT ROWID AS rid
    FROM   table_name
    ORDER BY DBMS_RANDOM.VALUE
  )
  WHERE ROWNUM <= 10000
)

---------------------------------------------------------------------------------------
| Id  | Operation                      | Name       | Rows | Bytes  | Cost | Time     |
---------------------------------------------------------------------------------------
|   0 | DELETE STATEMENT               |            |    1 |     37 |   13 | 00:00:01 |
|   1 |   DELETE                       | TABLE_NAME |      |        |      |          |
|   2 |    NESTED LOOPS                |            |    1 |     37 |   13 | 00:00:01 |
|   3 |     VIEW                       | VW_NSO_1   | 9968 | 119616 |   11 | 00:00:01 |
|   4 |      SORT UNIQUE               |            |    1 | 119616 |      |          |
| * 5 |       COUNT STOPKEY            |            |      |        |      |          |
|   6 |        VIEW                    |            | 9968 | 119616 |   11 | 00:00:01 |
| * 7 |         SORT ORDER BY STOPKEY  |            | 9968 | 119616 |   11 | 00:00:01 |
|   8 |          INDEX FAST FULL SCAN  | TN__ID__PK | 9968 | 119616 |    9 | 00:00:01 |
|   9 |     TABLE ACCESS BY USER ROWID | TABLE_NAME |    1 |     25 |    1 | 00:00:01 |
---------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
------------------------------------------
* 5 - filter(ROWNUM<=10000)
* 7 - filter(ROWNUM<=10000)

CREATE OR REPLACE PROCEDURE DEL_OBS(cuantos number)
IS
  TYPE obs_tab IS TABLE OF observations%ROWTYPE;
begin
  SELECT *
  BULK COLLECT INTO obs_tab
  FROM   (
    SELECT * FROM observations ORDER BY DBMS_RANDOM.VALUE
  )
  WHERE ROWNUM<=cuantos;

  FORALL i IN 1 .. obs_tab.COUNT
    DELETE FROM OBSERVATIONS
    WHERE  nplate    = obs_tab(i).nplate
    AND    odatetime = obs_tab(i).odatetime; 
END del_obs;